RE: SegFault on yyparse()

[Gautam Kapoor]

Hi Charlie,
YYLEX is a macro. It is making a call to the scanner to get the next token. I 
don't think "assigning to yychar" is causing the segfault. Please put a 
breakpoint into yylex() function and see where it is crashing.

Let us see the code snippet inside yylex() function to make out why the error 
occurs.

In a newer version of bison/flex, and depending on my other flags, I see this:
    /* Read a lookahead token.  */
    if (yychar == yyempty_)
      {
        YYCDEBUG << "Reading a token: ";
        yychar = yylex (&yylval, &yylloc);
      }

-regards
Gautam

-----Original Message-----
From: address@hidden [mailto:address@hidden On Behalf Of Charlie Lacroix
Sent: Wednesday, May 29, 2013 1:18 PM
To: address@hidden
Subject: SegFault on yyparse()

Hi,

I am a beginner with Flex/Bison tools. At my work, we have a project,
which contains bison files. It is an old version of bison : 2.3 ; and
an old version of Flex : 2.5.4. It compiles on this version, but on my
personal computer (with one of the last version of bison and flex), I
have a segmentation fault.

I used gdb to understand why, and the segfault appears on yyparse in
bla.tab.c, on the line below :

  if (yychar == YYEMPTY)
    {
      YYDPRINTF ((stderr, "Reading a token: "));
-->      yychar = YYLEX;
    }

I really don't understand why it works at my work, and not on my computer...
Can somebody help me? (sorry if I do not speak very well, I am a french ^^')
Thanks!

Best regards

Charlie Lacroix

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